CN111176363A - Current control circuit and method under low-temperature environment and electrical equipment - Google Patents
Current control circuit and method under low-temperature environment and electrical equipment Download PDFInfo
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- CN111176363A CN111176363A CN202010006308.2A CN202010006308A CN111176363A CN 111176363 A CN111176363 A CN 111176363A CN 202010006308 A CN202010006308 A CN 202010006308A CN 111176363 A CN111176363 A CN 111176363A
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/567—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation
Abstract
The invention discloses a current control circuit and method under a low-temperature environment and electrical equipment. Wherein, this circuit includes: the temperature sensing device comprises a voltage division resistor, a temperature sensing device and a control circuit; the first end of the divider resistor is connected with the positive electrode of a power supply, the second end of the divider resistor is connected with the first end of the temperature sensing device, the second end of the temperature sensing device is connected with the negative electrode of the power supply and used for changing the resistance value according to the environmental temperature and further changing the sampling voltage of the sampling point, the input end of the control circuit is connected with the sampling point, the output end of the control circuit is connected with the drive switch of the load circuit and used for adjusting the duty ratio of the drive switch in the load circuit according to the sampling voltage so as to control the current passing through the load. According to the invention, the problem of overlarge current output to a load when the electric appliance is started in a low-temperature environment can be avoided, and the stability of the electric appliance is improved.
Description
Technical Field
The invention relates to the technical field of electronic power, in particular to a current control circuit and method in a low-temperature environment and electrical equipment.
Background
Most of the existing electrical equipment adopts a constant current driving circuit, and in a cold environment, the parameter change of a circuit device is large, for example, the capacitance value of an electrolytic capacitor is greatly attenuated under a low-temperature condition. In the low-temperature starting process of the power supply, the fluctuation of the peak value of the output current is increased, the peak value is increased and exceeds the current tolerance value of the load of the electric appliance, the electric appliance can be damaged for a long time, and the stability and the service life of the electric appliance are influenced.
In the prior art, the current peak value is reduced mainly by adopting a method of increasing the capacitance value, the inductance value and the like in the constant current driving circuit, but the cost and the power supply volume are increased.
Aiming at the problem that the current output to the load is overlarge when the power supply is started in a low-temperature environment in the prior art, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a current control circuit, a method and electrical equipment in a low-temperature environment, and aims to solve the problem that in the prior art, when a power supply is started in the low-temperature environment, the current output to a load is overlarge.
In order to solve the above technical problem, the present invention provides a current control circuit in a low temperature environment, wherein the circuit includes:
the first end of the divider resistor is connected to the anode of the power supply, and the second end of the divider resistor is connected with the first end of the temperature sensing device and used for sharing the power supply voltage with the temperature sensing device;
the second end of the temperature sensing device is connected with the negative electrode of the power supply and is used for changing the resistance value according to the environmental temperature so as to change the magnitude of the sampling voltage of a sampling point, wherein the sampling point is positioned between the temperature sensing device and the voltage dividing resistor;
and the input end of the control circuit is connected with the sampling point, and the output end of the control circuit is connected with a driving switch of the load circuit and is used for adjusting the duty ratio of the driving switch according to the sampling voltage so as to control the current passing through the load.
Further, the temperature sensing device is a thermistor, and the resistance value of the temperature sensing device decreases with the increase of temperature.
Further, the control circuit includes:
the first input end of the comparator is connected with the sampling point, and the second input end of the comparator is connected with a reference voltage source and used for controlling an output level signal according to the magnitude of the sampling voltage;
the input end of the PWM chip is connected with the output end of the comparator and is used for controlling the output electric signal according to the level signal output by the comparator;
and the input end of the constant current chip is connected with the output end of the PWM chip, the output end of the constant current chip is connected with the driving switch of the load circuit, and the constant current chip is used for controlling the duty ratio of the driving switch according to the electric signal output by the PWM chip so as to control the current passing through the load.
Further, the comparator is specifically configured to output a high level signal when the sampling voltage is greater than or equal to the input reference voltage thereof, and output a low level signal when the sampling voltage is less than the input reference voltage thereof.
Further, the PWM chip is specifically configured to output a periodic pulse electrical signal when the comparator outputs a high level signal; when the comparator outputs a low level signal, a constant electric signal is output.
Further, the constant current chip is specifically configured to control the duty ratio of the driving switch to decrease when the PWM chip outputs the periodic pulse electrical signal, so as to control the current passing through the load to decrease, and control the duty ratio of the driving switch to remain unchanged when the PWM chip outputs the constant electrical signal, so as to control the current passing through the load to remain unchanged.
The invention also provides electrical equipment which comprises the current control circuit.
The invention also provides a current control method under a low-temperature environment, which is applied to the current control circuit and comprises the following steps:
acquiring sampling voltage of a sampling point between a temperature sensing device and a power supply anode, wherein the sampling voltage is reduced along with the rise of temperature;
and adjusting the duty ratio of a driving switch of a load circuit according to the sampling voltage so as to control the current passing through the load.
Further, adjusting a duty cycle of a driving switch of a load circuit according to the sampled voltage to control a magnitude of current through the load, includes:
controlling a level signal output by a comparator according to the magnitude of the sampling voltage;
controlling an electric signal output by a PWM chip according to the level signal output by the comparator;
adjusting the duty ratio of a driving switch of a load circuit according to the electric signal output by the PWM chip so as to control the current passing through the load;
the first input end of the comparator is connected with the sampling point, and the second input end of the comparator is connected with a reference voltage source; and the input end of the PWM chip is connected with the output end of the comparator.
Further, according to the magnitude of the sampling voltage, controlling a level signal output by the comparator, including:
if the sampling voltage is greater than or equal to the reference voltage of the comparator, controlling the comparator to output a high-level signal;
and if the sampling voltage is less than the reference voltage of the comparator, controlling the comparator to output a low-level signal.
Further, according to the level signal output by the comparator, the electric signal output by the PWM chip is controlled, including:
if the comparator outputs a high level signal, the PWM chip is controlled to output a periodic pulse electrical signal;
and if the comparator outputs a low level signal, the PWM chip is controlled to output a constant electric signal.
Further, adjusting the duty ratio of a driving switch of a load circuit according to the electric signal output by the PWM chip to control the current passing through the load comprises:
if the PWM chip outputs a periodic pulse electrical signal, controlling the duty ratio of the driving switch to be reduced so as to control the current passing through the load to be reduced, and if the PWM chip outputs a constant electrical signal, controlling the duty ratio of the driving switch to be kept unchanged so as to regulate the current passing through the load to be unchanged.
The invention also provides a computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the above-mentioned method.
By applying the technical scheme of the invention, the change of the resistance and the change of the sampling voltage are caused by the temperature change of the temperature sensing device, the change of the environmental temperature parameter is converted into the change of the sampling voltage, the duty ratio of the driving switch in the load circuit is controlled by the control circuit according to the change of the sampling voltage, the current passing through the load is further controlled, the problem of overlarge current output to the load when the load is started in a low-temperature environment can be avoided, and the stability of the electric appliance is improved.
Drawings
FIG. 1 is a block diagram of a current control circuit according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating the connection between a current control circuit and a load circuit according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating the connection between a current control circuit and a load circuit according to another embodiment of the present invention;
FIG. 4 is a diagram illustrating the connection between a current control circuit and a load circuit according to an embodiment of the present invention;
fig. 5 is a flowchart of a current control method according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be understood that although the terms first, second, etc. may be used in embodiments of the present invention to describe the connection terminals of the comparator or chip, these connection terminals should not be limited to these terms. These terms are only used to distinguish between different connection ends. For example, the first end may also be referred to as the second end, and similarly, the second end may also be referred to as the first end, without departing from the scope of embodiments of the present invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.
Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example 1
The present embodiment provides a current control circuit in a low temperature environment, and fig. 1 is a structural diagram of the current control circuit according to an embodiment of the present invention, as shown in fig. 1, the current control circuit includes: a voltage dividing resistor R1, a temperature sensing device 11 and a control circuit 12; the first end of divider resistance R1 inserts the power anodal, the first end of temperature-sensing device 11 is connected to the second end, the second end connection power negative pole of temperature-sensing device 11, it is the sampling point to get any point between the first end of temperature-sensing device 11 and divider resistance R1, temperature-sensing device 11 changes the resistance value according to ambient temperature, and then change the magnitude of the sampling voltage of sampling point, the inside material of temperature-sensing device 11 changes can lead to in the transform of ambient temperature value, and then lead to the resistance of temperature-sensing device 11 to change, change the change of ambient temperature parameter is the change of sampling voltage's size through temperature-sensing device 11, as control circuit 12's input signal.
The input end of the control circuit 12 is connected to the sampling point, and the output end is connected to the driving switch of the load circuit, and is used for adjusting the duty ratio of the driving switch in the load circuit according to the sampling voltage so as to control the magnitude of the current passing through the load.
The present embodiment is described below with reference to a specific load circuit, fig. 2 is a connection relationship diagram between a current control circuit and a load circuit according to an embodiment of the present invention, as shown in fig. 2, the load circuit includes a load 10, an inductor L1, and a driving switch Q1, which are sequentially interposed in series between an anode and a cathode of a switching power supply, two ends of the load 10 are connected in parallel with a capacitor C1, a line is led out between the inductor L1 and the driving switch Q1, the line is connected to the anode of the switching power supply through a freewheeling diode D1, the anode of the freewheeling diode D1 is connected to the line between the inductor L1 and the driving switch Q1, and the cathode is connected to the anode of the switching power supply.
The load circuit adjusts the current passing through the load 10 by the duty ratio of the driving switch Q1, and the control circuit 12 is connected to the driving switch Q1 of the load circuit, and it should be understood by those skilled in the art that the larger the duty ratio of the driving switch Q1, the larger the current passing through the load 10, therefore, the control circuit 12 can control the duty ratio of the driving switch Q1 by sending a control signal to the driving switch Q1, and further control the current passing through the load 10.
The temperature change of the surrounding environment will cause the temperature change of the temperature sensing element 11 itself, and further cause the magnitude of the sampling voltage of the sampling point to change, and the control circuit 12 outputs different control signals according to the magnitude of the sampling voltage, so as to control the magnitude of the current passing through the load 10. The temperature change through the temperature sensing device causes the change of resistance, and then causes the change of sampling voltage, converts the change of ambient temperature parameter into the change of sampling voltage, and control circuit 12 receives the change of sampling voltage to adjust the duty cycle of the drive switch in the load circuit according to the change of sampling voltage, and then control the electric current size through the load, when starting under can avoiding low temperature environment, the too big problem of electric current of output to load, improve the stability of electrical apparatus.
Example 2
In order to further realize the change of the sampling voltage with the temperature change, as shown in fig. 3, the temperature sensing device 11 is a thermistor R2, in this embodiment, the thermistor R2 is a negative temperature coefficient thermistor, the resistance value of the thermistor decreases with the temperature increase in the operating temperature range, because the resistance value of the temperature sensing device 11 decreases with the temperature increase, the resistance of the temperature sensing device 11 is larger at a lower temperature, the current in the closed loop formed by the power supply, the voltage dividing resistor R1 and the temperature sensing device 11 is smaller, the voltage drop before and after the voltage dividing resistor R1 is smaller, the voltage at the sampling point is larger, and when the resistance value decreases with the temperature increase, the sampling voltage is reduced along with the reduction of the resistance value, in the specific implementation, the lowest temperature and the highest temperature of the working environment of the load circuit can be tested in advance, the temperature range is recorded, the thermistor with the working temperature range including the temperature range is selected, in the application, a low-temperature threshold value is set, when the environment temperature is lower than the low-temperature threshold value, the current passing through the load can be increased, the resistance value corresponding to the low-temperature threshold value is found by inquiring the R-T table of the selected negative temperature coefficient thermistor, namely the corresponding relation table of the resistance and the temperature, the value of the sampling voltage under the environment temperature is calculated by combining the resistance value of the divider resistor R1 according to the rule that the series circuit voltage is in direct proportion to the resistance value, and the control circuit outputs a corresponding control signal according to the value of the sampling voltage.
In another embodiment of the present invention, the thermistor R2 may be a positive temperature coefficient thermistor, the resistance value of which increases as the temperature thereof increases, and when the thermistor R2 is a positive temperature coefficient thermistor, the positions of the voltage dividing resistor R1 and the thermistor R2 need to be interchanged, the thermistor R2 is connected to the positive power supply, and the voltage dividing resistor R1 is connected to the negative power supply, but since the thermistor itself generates heat after being energized, the thermistor R2 is preferably a negative temperature coefficient thermistor in order to avoid interference caused by the heat generation of the resistor.
In order to realize that the control circuit outputs different control signals according to the magnitude of the sampling voltage, as shown in fig. 3, the control circuit 12 includes: a comparator 121, having a first input end connected to the sampling point and a second input end connected to a reference voltage source, for controlling an output level signal according to the magnitude of the sampling voltage; when the sampling voltage is greater than or equal to the input reference voltage, it indicates that the ambient temperature is lower than or equal to the low-temperature threshold, the comparator outputs a high-level signal, so that the subsequent circuit realizes a function of controlling the current passing through the load to be reduced, and when the sampling voltage is less than the input reference voltage, it indicates that the ambient temperature is higher than the low-temperature threshold, the comparator outputs a low-level signal, so that the subsequent circuit realizes a function of controlling the current passing through the load to be unchanged.
In order to realize that different electric signals are output according to the high level or low level signal output by the comparator 121, as shown in fig. 3, the control circuit 12 further includes: a PWM chip 122, an input terminal of the PWM chip 122 is connected to the output terminal of the comparator 121, and is configured to control the output electrical signal according to the high level or low level signal output by the comparator 122, specifically, when the comparator 121 outputs the high level signal, the PWM chip 122 outputs a periodic pulse electrical signal; when the comparator 121 outputs a low level signal, the PWM chip 122 outputs a constant electric signal.
To further realize the control of the duty cycle of the driving switch Q1 according to the electrical signal output by the PWM chip 122, the control circuit 12 further includes: the constant current chip 123, the input end of the constant current chip 123 is connected to the output end of the PWM chip 122, the output end is connected to the driving switch of the load circuit, and is used for controlling the duty ratio of the driving switch according to the electrical signal output by the PWM chip, so as to control the magnitude of the current passing through the load, specifically, when the PWM chip 122 outputs a periodic pulse electrical signal, the duty ratio of the driving switch Q1 is controlled to be reduced, that is, the time for turning on the driving switch Q1 in the same period is controlled to be shortened, so as to control the average current passing through the load to be reduced, and the peak value of the current passing through the load to be reduced, and when the PWM chip outputs a constant electrical signal, the duty ratio of the driving switch is controlled to be kept.
Through the current control circuit of this embodiment, can realize when load circuit is in low temperature environment, the sampling voltage risees to make the comparator output high level, and then control PWM chip output periodic pulse signal to constant current chip 123, under the effect of periodic pulse signal, the duty ratio of control drive switch is less, reduces with the electric current of control through the load, avoids passing through the current of load too big, when load circuit is in normal temperature, the duty ratio of control drive switch is unchangeable, keeps current unchangeable.
Example 3
The present embodiment provides a current control circuit under a low temperature environment, which is specifically applied to a load circuit whose load is an LED lamp, and fig. 4 is a connection relationship diagram of the current control circuit and the load circuit according to the embodiment of the present invention, as shown in fig. 4, the load circuit includes: the LED, the inductor L2 and the driving switch tube Q2 are sequentially connected in series between the positive electrode and the negative electrode of the switching power supply, a capacitor C2 is arranged at two ends of the LED in parallel, a line is LED out between the inductor L2 and the driving switch tube Q2 (namely the driving switch Q1 in the embodiment), the line is connected with the positive electrode of the switching power supply through a fly-wheel diode D2, the anode of the fly-wheel diode D2 is connected with the line between the inductor L2 and the driving switch tube Q2, and the cathode of the fly-wheel diode D2 is connected with the positive electrode of the switching power supply.
In order to supply power to the load circuit and the current control circuit by using the same power source, as shown in fig. 4, the current control circuit further includes a core T1 and a winding L3, an inductor L2 of the load circuit is wound on one side of the core T1, and a winding L3 is wound on the other side of the core T1, and an induced voltage is generated by the core T1 and the winding L3 based on the current flowing in the L2, so as to supply power to a voltage dividing resistor R3 (i.e., the voltage dividing resistor R3 in the above embodiment) and a thermistor R4 (i.e., the thermistor R2 in the above embodiment).
The current control circuit further includes a comparator 41 (i.e., the comparator 121 in the above-mentioned embodiment), a PWM chip 42 (i.e., the PWM chip 122 in the above-mentioned embodiment), and a constant current dimming chip 43 (i.e., the constant current chip 213 in the above-mentioned embodiment), in the prior art, the constant current circuit adopts a step-down mode, and by sampling the current flowing through the LED, the proportion of the on time of the driving switch in the LED circuit in the same period, i.e., the duty ratio, is controlled, so as to achieve the stability of the output current of the switching power supply, i.e., the stability of the current flowing through the LED lamp, and in addition, a high temperature protection circuit can be added to prevent the high temperature damage of the power supply. In a low-temperature environment, the stability of the output current at the time of starting is affected by the change of the capacitance parameter of the capacitor C2, and the current peak value becomes large.
In order to solve the above problem, in the present embodiment, the induced voltage generated in the winding L3 supplies power to the voltage dividing resistor R3 and the thermistor R4, a point is arbitrarily selected between the voltage dividing resistor R3 and the thermistor R4 as a sampling point, the sampling point is connected to the inverting input terminal of the comparator 41 and compared with the reference voltage Vref1 input to the positive input terminal of the comparator 41, the output terminal of the comparator 41 is connected to the input terminal of the PWM chip 42, the PWM chip 42 is controlled to output a high-frequency pulse driving signal, the output terminal of the PWM chip 42 is connected to the signal receiving pin of the constant-current dimming chip 43, and the constant-current dimming chip 43 controls the dimming mode of the constant-current dimming chip 43, that is, the duty ratio of the driving switch is controlled to decrease or not change according to the high-frequency pulse. When the LED power supply is in a low-temperature environment, the resistance value of the thermistor R3 is large, when the LED power supply is started at the temperature, the sampling voltage of a sampling point is larger than or equal to the reference voltage Vref1, the PWM chip 42 is activated, a high-frequency pulse driving signal is output, the constant-current dimming chip 43 enters a PWM dimming mode, the switching tube Q2 is driven, the duty ratio of the driving switching tube Q2 is reduced, the current passing through the LED is reduced, and the smooth starting of the output current is realized. When the switching power supply works for a period of time, the switching power supply can generate heat, and due to the fact that the size of the circuit is small and components are concentrated, the resistance value of the thermistor R4 is reduced along with the rise of temperature, so that the sampling voltage is reduced, when the sampling voltage is lower than Vref1, the PWM module is locked and outputs a constant electric signal, the constant-current dimming chip enters a non-dimming mode, and a normal current value is output to drive the LED light source to be lightened, so that stable light emitting is realized.
In addition, a filter circuit and a DC/DC converter (not shown in the figure) are sequentially connected between the sampling point and the comparator 41, the filter circuit is used for filtering harmonics in the sampled voltage, and the DC/DC converter is used for converting the high-voltage direct current output by the filter circuit into low-voltage direct current.
The invention fully utilizes the function of the constant current circuit device, realizes the output smooth start of the constant current circuit in the low-temperature environment, avoids overlarge current passing through an LED during low-temperature start, and reduces the influence of a capacitor on the circuit performance at low temperature.
Example 4
The embodiment provides an electrical device, which comprises the current control circuit in the low-temperature environment.
Example 5
The present embodiment provides a current control method in a low temperature environment, which is applied to the current control circuit, and fig. 5 is a flowchart of the current control method according to the embodiment of the present invention, as shown in fig. 5, the method includes:
s101, acquiring sampling voltage of a sampling point between a temperature sensing device and a power supply anode, wherein the sampling voltage is reduced along with the rise of temperature, the sampling point is positioned between a divider resistor and the temperature sensing device, the value of the sampling voltage is determined by the resistance of the temperature sensing device because the resistance value of the divider resistor is constant, and the sampling voltage is increased because the temperature sensing device is a negative temperature coefficient thermistor and the lower the ambient temperature is, the higher the resistance value of the temperature sensing device is;
and S102, adjusting the duty ratio of a driving switch of the load circuit according to the sampling voltage so as to control the current passing through the load.
The control circuit includes: the first input end of the comparator is connected with the sampling point, and the second input end of the comparator is connected with a reference voltage source; the input end of the PWM chip is connected to the output end of the comparator, and in order to control the magnitude of the current passing through the load according to the change of the sampling voltage, step S102 includes: controlling a level signal output by the comparator according to the magnitude of the sampling voltage; specifically, if the sampling voltage is greater than or equal to the reference voltage of the comparator, which indicates that the temperature ambient temperature is lower than or equal to the low-temperature threshold, the problem of excessive current passing through the load is caused, so that the comparator is controlled to output a high-level signal, so that the subsequent circuit realizes the function of controlling the current passing through the load to be reduced; if the sampling voltage is less than the reference voltage of the comparator, it is indicated that the temperature environment temperature is higher than the preset low-temperature threshold, and the problem of excessive current passing through the load cannot be caused, so that the comparator is controlled to output a low-level signal, so that a subsequent circuit realizes the function of controlling the current passing through the load to be unchanged, wherein the reference voltage is determined according to the sampling voltage corresponding to the low-temperature threshold, and the voltage value of the reference voltage can be equal to the sampling voltage corresponding to the low-temperature threshold.
Next, controlling the electrical signal output by the PWM chip according to the level signal output by the comparator, specifically, controlling the PWM chip to output a periodic pulse electrical signal if the comparator outputs a high level signal; and if the comparator outputs a low-level signal, the PWM chip is controlled to output a constant electric signal.
And finally, adjusting the duty ratio of a driving switch of a load circuit according to the electric signal output by the PWM chip through a constant current chip so as to control the current passing through the load, specifically, if the PWM chip outputs a periodic pulse electric signal, controlling the duty ratio of the driving switch to be reduced, namely, controlling the conduction time of the driving switch to be shortened in the same period, so as to control the average current passing through the load in the period to be reduced, and reduce the current peak value passing through the load, and if the PWM chip outputs a constant electric signal, controlling the duty ratio of the driving switch to be kept unchanged, so as to adjust the current passing through the load to be unchanged.
According to the current control method under the low-temperature environment, the ambient temperature is reflected through the magnitude of the reference voltage, and then the duty ratio of the driving switch in the load circuit is controlled according to the reference voltage, so that the current passing through the load is controlled, the problem that the current flowing through the load is too large when the load circuit is started under the low-temperature environment can be solved, and the stability of the load can be effectively improved.
Example 6
The present embodiment provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the above-described method.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (13)
1. A current control circuit, the circuit comprising: the temperature sensing device comprises a voltage division resistor, a temperature sensing device and a control circuit;
the first end of the divider resistor is connected to the anode of the power supply, and the second end of the divider resistor is connected with the first end of the temperature sensing device and used for sharing the power supply voltage with the temperature sensing device;
the second end of the temperature sensing device is connected with the negative electrode of the power supply and is used for changing the resistance value according to the environmental temperature so as to change the magnitude of the sampling voltage of a sampling point, wherein the sampling point is positioned between the temperature sensing device and the voltage dividing resistor;
and the input end of the control circuit is connected with the sampling point, and the output end of the control circuit is connected with a driving switch of the load circuit and is used for adjusting the duty ratio of the driving switch according to the sampling voltage so as to control the current passing through the load.
2. The circuit of claim 1, wherein the temperature sensing device is a thermistor and the resistance decreases with increasing temperature.
3. The circuit of claim 1, wherein the control circuit comprises:
the first input end of the comparator is connected with the sampling point, and the second input end of the comparator is connected with a reference voltage source and used for controlling an output level signal according to the magnitude of the sampling voltage;
the input end of the PWM chip is connected with the output end of the comparator and is used for controlling the output electric signal according to the level signal output by the comparator;
and the input end of the constant current chip is connected with the output end of the PWM chip, the output end of the constant current chip is connected with the driving switch of the load circuit, and the constant current chip is used for controlling the duty ratio of the driving switch according to the electric signal output by the PWM chip so as to control the current passing through the load.
4. The circuit of claim 3, wherein the comparator is specifically configured to output a high signal when the sampled voltage is greater than or equal to the reference voltage at its input and to output a low signal when the sampled voltage is less than the reference voltage at its input.
5. The circuit of claim 4, wherein the PWM chip is specifically configured to output a periodic pulsed electrical signal when the comparator outputs a high level signal; when the comparator outputs a low level signal, a constant electric signal is output.
6. The circuit of claim 5, wherein the constant current chip is specifically configured to control the duty ratio of the driving switch to decrease when the PWM chip outputs the periodic pulse electrical signal, so as to control the current passing through the load to decrease, and to control the duty ratio of the driving switch to remain unchanged when the PWM chip outputs the constant electrical signal, so as to control the current passing through the load to remain unchanged.
7. An electrical appliance comprising a current control circuit as claimed in any one of claims 1 to 6.
8. A current control method applied to the current control circuit according to any one of claims 1 to 6, the method comprising:
acquiring sampling voltage of a sampling point between a temperature sensing device and a power supply anode, wherein the sampling voltage is reduced along with the rise of temperature;
and adjusting the duty ratio of a driving switch of a load circuit according to the sampling voltage so as to control the current passing through the load.
9. The method of claim 8, wherein adjusting a duty cycle of a drive switch of a load circuit according to the sampled voltage to control a magnitude of current through the load comprises:
controlling a level signal output by a comparator according to the magnitude of the sampling voltage;
controlling an electric signal output by a PWM chip according to the level signal output by the comparator;
adjusting the duty ratio of a driving switch of a load circuit according to the electric signal output by the PWM chip so as to control the current passing through the load;
the first input end of the comparator is connected with the sampling point, and the second input end of the comparator is connected with a reference voltage source; and the input end of the PWM chip is connected with the output end of the comparator.
10. The method of claim 9, wherein controlling the level signal output by the comparator according to the magnitude of the sampled voltage comprises:
if the sampling voltage is greater than or equal to the reference voltage of the comparator, controlling the comparator to output a high-level signal;
and if the sampling voltage is less than the reference voltage of the comparator, controlling the comparator to output a low-level signal.
11. The method of claim 9, wherein controlling the electrical signal output by the PWM chip according to the level signal output by the comparator comprises:
if the comparator outputs a high level signal, the PWM chip is controlled to output a periodic pulse electrical signal;
and if the comparator outputs a low level signal, the PWM chip is controlled to output a constant electric signal.
12. The method of claim 9, wherein adjusting a duty cycle of a drive switch of a load circuit to control a magnitude of current through the load according to the electrical signal output by the PWM chip comprises:
if the PWM chip outputs a periodic pulse electrical signal, controlling the duty ratio of the driving switch to be reduced so as to control the current passing through the load to be reduced, and if the PWM chip outputs a constant electrical signal, controlling the duty ratio of the driving switch to be kept unchanged so as to regulate the current passing through the load to be unchanged.
13. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the method according to any one of claims 8 to 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010006308.2A CN111176363A (en) | 2020-01-03 | 2020-01-03 | Current control circuit and method under low-temperature environment and electrical equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010006308.2A CN111176363A (en) | 2020-01-03 | 2020-01-03 | Current control circuit and method under low-temperature environment and electrical equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111176363A true CN111176363A (en) | 2020-05-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010006308.2A Pending CN111176363A (en) | 2020-01-03 | 2020-01-03 | Current control circuit and method under low-temperature environment and electrical equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111176363A (en) |
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2020
- 2020-01-03 CN CN202010006308.2A patent/CN111176363A/en active Pending
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